The statistical nature of baseball makes it possible to test many of its most trusted axioms against real empirical data, and this one is a classic example.

Because throwing a curveball exerts so much torque on the elbow even for Major League pitchers, conventional wisdom holds that it's risky for young pitchers to start throwing breaking balls. But last year, when separate research teams decided to check whether this truism is indeed true, they couldn't find the effect. Monitoring the arms of 9- to 14-year-old pitchers in simulated games, they found that curveballs stressed the elbow less than fastballs.

Glenn Fleisig, who led one study, said that if there's a danger to young arms, it's the long games and long seasons. It's not that curveballs destroy young arms, ESPN the Magazine wrote in a follow-up. It's that kids who can throw a mean curve and dominate the opposition get put in the game too often--or stay in the game too long.

All this led to a kerfuffle on the sports talk circuit, including some indignation that the researchers would dare defend the dreaded curve. As the scientists found out, it can be treacherous to go against preconceived notions.